回火温度对Cr5NiMoVNb支承辊用钢组织与性能的影响

为了研究回火温度对Cr5NiMoVNb支承辊用钢显微组织及力学性能的影响,采用扫描电镜、X射线衍射仪、洛氏硬度计、拉伸试验机和冲击试验机对不同回火温度下Cr5NiMoVNb钢进行了测试。结果表明:Cr5NiMoVNb钢的回火态组织以回火马氏体为主,并含有少量的残留奥氏体。回火过程中伴随有碳化物的析出和马氏体相变。随着回火温度的升高,Cr5NiMoVNb钢的强度(抗拉强度与屈服强度)与硬度逐渐降低,塑性(伸长率与断面收缩率)与韧性(冲击吸收能量)逐渐提高。在试验选定范围内,520 ℃回火的Cr5NiMoVNb钢的硬度、抗拉强度、断面收缩率和冲击吸收能量分别达到53.5 HRC、1735 MPa、25.2%和7.3 J,综合力学性能最优。

Effect of tempering temperature on microstructure and properties of Cr5 NiMoVNb steel for backup roll

Effect of tempering temperature on microstructure and mechanical properties of Cr5 NiMoVNb steel for backup roll was studied by means of scanning electron microscope,X-ray diffractometer,Rockwell hardness tester,tensile tester and impact tester.The results show that tempered martensite-predominantly matrix is observed in Cr5 NiMoVNbb steel with a small amount of residual austenite when temped at different temperatures.The precipitation of carbides and the phase transition of residual austenite occur during tempering process.The strength(tensile strength and yield strength)and the hardness of Cr5 NiMoVNb steel gradually decrease with the increase of tempering temperature.The plasticity(reduction of area)and the toughness(impact absorbed energy)of the Cr5 NiMoVNb steel gradually increase with the increase of tempering temperature.When tempering temperature is 520℃,the preferable mechanical properties of Cr5 NiMoVNb steel are obtained,leading the hardness,tensile strength,reduction of area and impact absorbed energy to 53.5 HRC,1735 MPa,25.2%and 7.3 J,respectively.